[mpiwg-sessions] question about section 8.3 and MPI_COMM_SELF

[Pritchard Jr., Howard]

Hi Aurelien,

responses interleaved below:

--
Howard Pritchard
B Schedule
HPC-ENV
Office 9, 2nd floor Research Park
TA-03, Building 4200, Room 203
Los Alamos National Laboratory


From: mpiwg-sessions <mpiwg-sessions-bounces at lists.mpi-forum.org<mailto:mpiwg-sessions-bounces at lists.mpi-forum.org>> on behalf of Aurelien Bouteiller <bouteill at icl.utk.edu<mailto:bouteill at icl.utk.edu>>
Reply-To: MPI Sessions working group <mpiwg-sessions at lists.mpi-forum.org<mailto:mpiwg-sessions at lists.mpi-forum.org>>
Date: Tuesday, August 21, 2018 at 7:41 AM
To: MPI Sessions working group <mpiwg-sessions at lists.mpi-forum.org<mailto:mpiwg-sessions at lists.mpi-forum.org>>
Subject: Re: [mpiwg-sessions] question about section 8.3 and MPI_COMM_SELF

Howard,

A similar issue has been discussed during the last virtual meeting about what happens to errors in MPI_INIT (in which it is not guaranteed that MPI_COMM_SELF) is completely initialized yet, and error handlers had no chance to be set by users yet).

One of the feedback of the call is that in such cases, returning an error code is a desired outcome. That would particularly apply to session_init.

I like this idea!  I’ll put some text into 8.3 stating this behavior when using the Peer to Peer model for initialization.


For the rest of the session operations, it could be beneficial to be able to set explicitly (i.e. with a session api call) what is the default/fallback error handler for when the MPI_COMM_SELF object has not been created, and the rules for precedence between these mechanisms when both are in play. I do not remember the group discussing these issues in much more details.

Agreed.  We need to come up with some way to deal with the way MPI_COMM_SELF is used currently as a grab bag of things.


Best,
Aurelien


On Aug 20, 2018, at 14:20, Pritchard Jr., Howard <howardp at lanl.gov<mailto:howardp at lanl.gov>> wrote:

Hi Folks,

Does anyone in the WG recall what our thoughts were concerning
the case when MPI encounters an error in an MPI function
not associated with a particular communicator, file, window, or
(now) session?

I’m concerned about this sentence in 8.3:

When using the MPI calls that are not related to any objects are considered to be attached to the communicator
MPI_COMM_SELF.

Looking at the old power point slide deck, this problem is mentioned, but not
addressed.

Howard

--
Howard Pritchard
B Schedule
HPC-ENV
Office 9, 2nd floor Research Park
TA-03, Building 4200, Room 203
Los Alamos National Laboratory

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